Discuss the impact of CSS 'will-change' property on web performance.

Certainly! The will-change CSS property is an exciting feature that essentially gives developers the ability to inform the browser ahead of time about which elements are expected to change. This could be in terms of layout, content, scroll position, or even z-index. The purpose of will-change is to allow the browser to perform any necessary optimizations beforehand, thereby improving the page's rendering performance and providing a smoother user experience. Now, let's delve a bit deeper into how will-change works and why it's such a powerful tool for web performance. When we use will-change, we're essentially telling the browser, "Hey, pay attention to this element because I'm going to be changing its properties soon." This heads-up allows the browser to set up any optimizations in advance, such as moving the element to its own layer (also known as layer promotion)...